of middletown



Patented May 21,1929.

' UNITED S -res PATENT OFFICE.

ALPHONBUS F. MURPHY, OF ZANESVILLE, AND WILLIAI J'ONE S, OF MIDDLETOWN, 4

4 OHIO, ABSIGNOBS TO THE AMERICAN ROLLING OHIO, A CORPORATION OI OHIO.

KILL OOHPANY, OF MIDPLETOWN,

I PROCESS OF TREATING SILIOON STEEL.

No Drawing.

. Our invention relates to processes for the formation of smooth finish, scale free electrical sheets, formed of high silicon alloy steel, which sheets have been both pickled and an- 5 nealed.

Otto Graef in his Patent No. 1,17 3,951, dated February 29, 1916, refers to the method of preparing silicon steel sheets by first pickling them, and then annealing them, in order to produce a scale free product, but in his patent states that by first annealing and then pickling, he obtains better electrical properties.

Our investigations with both processes have resulted in development of a rocess, whereby a certain type of pickling o silicon steel sheets, followed by a cold rolling to impart surface conditions, and followed by the usual annealing treatment to impart electri cal properties, will result in a sheet of smooth finish, with the electrical properties as high or hi her than can be obtained with the process o Graef, and with a space factor which is close to 100 per cent.

Among other thin s, the Graef patent fails to state the nature 0% the pickling step of his PTO-JESS. or of old processes which he believes himself to have improved, and we find that in order to remove the heavy mill scale resulting from the rolling of the sheets, it is necessary to provide a pickling solution and proper temperatures therefor, which will lift the scale fully, without pitting the sheets.

We will describe in detail the preferred as mode of practicing our process, and will set forth the novelty inherent therein in the claims that follow.

In preparing the sheets for our treatment, they are hot rolled inpacks, and the packs 40 o ened, and the sheets'straightened out, as by giving them a ass between rolls. the object being to provi e a sheet which is flat. so as to be readily handled in the treatment to follow. We thus pass the stripped sheets from 46 the pack through a cold roll mill. either in the presence of water or dry, and if we can avoid this flattening process, we prefer to do so, since the finish to the sheet is imparted by a cold roll treatment after pickling, and 50 a preliminary cold rolling tends to make the mill scale more adherent. Any mode of flattening the sheets following stripping the packs, will serve our purpose.

The sheets from the flattening step, if this Application filed April 15,

is required,-are then passed to the pickling bath wh1ch is made up of a solution of sulphur1c acid as usual in pickling, to which may be added with advantage, some suitable controlling solution such as are on the market. Incontrol is the trade name of a suitable product for this purpose. The object of controlling the pickling action is to lift the scale without rupturing the sheet. Sub stances such as Incontrol contain gelatinous materials, blood and preservatives and retard hydro en development by shielding the cathodes uring electrolytic action.

' When the sheet has been pickled so as to be free of scale it is thoroughly washed, with the final was ing being given by a basic solut on, such asa solution of water and air slaked hme, to neutralize the acid. Some other neutralizing solution can be employed instead of the lime, and following the neutralization, the sheets are thoroughly boshed and scrubbed mechanically, after which a mechanical separator is imposed on the sheets, such as by spraying them with air slaked lime solutions w ich dries to form a coating that keeps the sheets from adhering to each other during annealing.

The sheets, free from it holes, and free from any acid, and coate with a mechanical separator, are piled in annealing boxes and given an annealing to produce the required magnetic properties. The sheets are. then cold rolled, by being given one or morepasses, preferably in the resence of water.

If this cold rollmg be omitted, the results will be satisfactory, but not so valuablein producing a clean, smooth surface, as if the cold rolling is followed. Thus, the sheets without any surface impartin cold rolling, will be better than sheets w ich-have not been pickled before annealing, but will not be so excellent as those which we produce by addingthe cold rollingstep.

The sheets are then again piled in annealing boxes and annealed at the temperatures and time periods known to be necessary for retaining and producing high electrical factor is meant the pro ortion of solid metal to solid metal, plus sur ace irregularities and scale or oxide, in a pile made up ofa number of layers of the sheets.

Having thus described our inventionfwhat we claim as new and desire to secure by Letters Patent, is z- 1. A process for preparing silicon steel 7 sheets for electrical purposes, which consists in passing the manufactured sheets through a pickling treatment, then washing sheet, neutralizingthe sheets by treating with a basic solution, imposing a mechanical separator on the sheets, and annealing the product to produce electrical qualities, and finally giving a smooth surface to the sheets as hy cold rolling, followed by a second annealing.

3. A process for preparing silicon steel sheets for electrical purposes, which consists in assing the manufactured sheet through a pic ling treatment to remove the scale resulting in manufacture of the sheet, then cleaning the sheet, then neutralizing the sheets and imposing a mechanical separator thereon, and finally'nnnealing the sheets to give electrical properties in two separate cycles. intermediate of which "cycles a surface smoothing treatment is imparted to the sheets,

ALPHONSUS F MURPHY. WILLIAM JONES. 

